Munster reached the Champions Cup knockout stages for a record 17th time with a runaway 48-3 bonus-point victory over Castres at Thomond Park.

The kick-off was delayed by three hours due to heavy rain in Limerick, but the efforts of the ground staff ensured the game went ahead as Munster — advancing as Pool 4 winners — set up a home quarter-final against Toulon.

Man-of-the-match Keith Earls’ third try in as many games made it 13-3 at half-time, with the hosts taking advantage of Thomas Combezou’s yellow card after a slow start.

News came through at the break that La Rochelle’s failure to notch a bonus point against Harlequins meant Munster needed just a win to seal that prized home quarter-final. Nonetheless, Johann van Graan’s men pushed on for maximum points.

Rhys Marshall’s maul effort and a scintillating bonus-point score from Simon Zebo, either side of a penalty try, had Castres out for the count and replacements Alex Wootton and James Cronin made it five unanswered tries in the second half.

The French side certainly came to play and they dominated the early possession without creating scoring opportunities, their best attacking moment coming when captain Robert Ebersohn broke through midfield in the ninth minute.

Full-back Zebo was rock solid under the high ball, but Jean Kleyn’s goading of an opponent saw a penalty reversed on the quarter hour and Rory Kockott kicked Castres into a deserved lead.

Despite the injury-enforced departure of Dave Kilcoyne, the Munster pack, with Kleyn to the fore, were rewarded for their direct play entering the second quarter. Ian Keatley knocked over two penalties from in front of the posts to put them in front.

The penalties were mounting against Castres and centre Combezou paid the price for his team’s indiscipline on the half-hour mark. Opting for a scrum, Munster flung the ball wide through Conor Murray, Rory Scannell and Zebo to put ace-poacher Earls over in the left corner.

Keatley added a terrific conversion before the home side missed out on a second try before the interval, Chris Farrell making a powerful break but Murray was unable to connect with Andrew Conway on his side.

Once hooker Marshall crossed at the end of a 44th-minute maul, Munster were in full control as they continued to build from their strong set-piece platform.

CJ Stander was held up on a bulldozing drive past the line, but a bout of scrum pressure saw Castres leak a succession of penalties. Earls and Murray had close-range tries ruled out before referee Ben Whitehouse binned replacement prop Daniel Kotze and followed up with the awarding of a penalty try.

Earls was devastating on a 58th-minute kick return, scurrying up towards the Castres 22 before passing for Zebo to evade the final two defenders and register the bonus point.

Keatley converted and his replacement JJ Hanrahan added the extras to Wootton’s maiden European score, which saw him wriggle over after Munster ball had gone loose on the ground, and a last-minute touchdown from prop Cronin via another punishing lineout drive put icing on the cake.